You need to do a hazard analysis and risk assessment and, if you have a credible scenario where you can reduce the oxygen content in the laboratory to 19.5% or less then you really need to consider oxygen monitoring and alarms. Given the high exhaust rates in most laboratories this usually (usually) is only an issue if you have a large number of liquid cryogenic dewars or a house cryogenic system, Typically catastrophic failure of a dewar is not considered a credible scenario as these instances are exceptionally rare.

In my experience, except for very small laboratories, or those with very low exhaust rates (like SEM labs) oxygen monitoring is not required unless the owners try to stack a 10 day supply of cryogens on hand at all times. (I.e. they are simply storing way too much.)

Hi everyone,

‘Just doing some benchmarking. My question is what does your institution’s assessment look like in order to determine when oxygen deficiency monitoring is needed for a proposal to use a cryogen liquid in a lab?

I look forward to hearing responses.

Thanks, Ellen

Ellen Sweet

Laboratory Ventilation Specialist

Department of Environmental Health and Safety, Cornell University

American Chemical Society, Division of Chemical Health and Safety

315-730-8896

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